Geomagnetically induced currents measured at low latitude during the space disturbances on 07-08 September, 2017
Bibliographic record
Abstract
Geomagnetically induced currents (GICs) were rst described by W. H. Barlow in 1849 as anomalous currents in telegraphic wires. These phenomena are currently understood as a ground eect arising from a chain of events in the Sun-Earth system. They are mainly observed at power networks and their amplitudes are controlled by a combination of geophysical conditions and network parameters. The magnetic disturbances detected on the ground came from the coupling of highly disturbed solar wind plasma propagating through the interplanetary medium which eventually impinges on the Earth's magnetosphere. The perturbed magnetosphere-ionosphere coupling can produce intense currents systems that can induce strong geoelectric elds at the Earth's surface, which in turn generate currents that can ow through grounded technological infrastructure as it oers low-resistance pathways. The available GIC datasets show that at high latitudes GIC records can reach hundreds of Amperes, leading to failure at transformers, such as reported at Hydro-Quebec, in Canada in 1989 and at Malmo, in Sweden in 2011. Due to the higher GIC intensities recorded at auroral regions, the GIC data at mid-to-low latitudes had been scarce. However, more recent works have shown that GIC can reach tenths of Amperes during intense sudden commencement and at the peak of geomagnetic storms. Despite intense geomagnetic storms are rare during the solar cycle declining phase, on the period of 04-06 September 2017 solar activity was increased due to the evolution of the active region 2673, thus it was observed two CME propagating Earthwards. The geomagnetic storm initiated at the beginning of 07 September evolving to one day long main phase as high as -140 nT. Besides the geomagnetic disturbances due to the ICME shock, also at least two intense solar ares (at 06 and 10 September 2017) causing spike disturbances in the geomagnetic eld measured at the ground. Considering the relevance of the intense space disturbance during the solar cycle declining phase, in this work, we use de Lethinen-Pirjola model to calculated GIC at low latitude power network located at Brazil and Uruguay during the period of the disturbance. The GIC results obtained during the solar cycle declining phase, compared to the long-term survey available at literature, are used to verify the signicance of GIC intensity observed at low latitude measured after the ICME disturbance and also with the are geomagnetic disturbance registered after a long-term of solar cycle condition.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".